Red azo dye and process of making same.



UNITED STATES PATENT oFFIoE.

HUGO GELDERMANN, OF GROSS-LIGHTERFELDE-OST, NEAR BERLIN, GERMANY, ASSIGNOR TO AOTIEN GESELLSOHAFT FUR ANILIN FABRIKATION, OF BERLIN, GERMANY.

Specification of Letters Patent.

Patented Feb. 25, 1908.

Application filed November 6. 1907- Serial No. 400,986.

To all whom it may concern:

',::Be it known that I, HUGO GELDERMANN, a citizen of the German Empire, residing at Gross-Lichterfelde-Ost, near Berlin, Germany, and whose post-office address is Gross- Lichterfelde-Ost, near Berlin, Grabenstrasse 12, have invented certain new and useful Improvements in New Red Azo Dyestuffs and Processes of Making Same, of which the following is a specification.

I have found that new red azo-dyestuffs can be obtained by combining the tetrazocompound of a monoor polysulfonic acid of para-para -diaminophenylether with 2 molecular proportions of beta-naphthol. The products which I thus obtain dye wool in an acid bath without a mordant clear red tints which are more especially distinguished by a very good fastness to milling.

As to the production of the sulfonic acids of para-diaminophenylether serving as parent material for the manufacture of my new dyestuffs, I give the following particulars. Such a sulfonic acid of para-para -diaminophenylether, which ether is described in the Berichte der Deutschen Ohemt'schen Gesellschaft, Vol. XXIX, page 1446 may be obtained by the sulfonation of this ether. On the other hand such monoor disulfonic acid may also be prepared by condensing para nitrochlorobenzeneortho sulfonic acid or a salt thereof with an alkali salt of para-nitrophenol or of a sulfonic acid of para-nitrophenol; finally a para-diaminophenylether-disulfonic acid may also be manufactured by sulfonating the corresponding monosulfonic acid by the action of hot fuming sulfuric acid. Thus for instance I mention the para-aminophenylether disulfonic acid, which may be obtained by the ac-.

tion of fuming sulfuric acid on the le -diaminophenylether2-monosulfonic acid; this new acid is difficultly soluble in water and can easily be diazotized in the usual manner by means of sodium nitrite and hydrochloric acid. The tetrazo-compound thus obtained is only slightly colored and also difficultly soluble in water. i

The following example may serve to illustrate my invention, the parts being by weight: 20.2 parts of the sodium salt of the para para diaminophenylether disulfonic acid, which acid may be obtained by the action of fuming sulfuric acid on the le -diaminophenylether-2-monosulfonic acid, are diazotized in the usual manner in an aqueous solution by means of 55 parts of hydrochloric acid of 12 Baum specific gravity and 7 parts of sodium nitrite. The tetrazocompound thus obtained is allowed to react on an aqueous solution of 15 parts of beta naphthol in 12 parts of soda lye of 40 Baum specific gravity, such quantity of sodium carbonate being added that the solution has an alkaline reaction throughout the whole operation. The formation of the dyestuff being finished, the dyestuff separates; the product of the reaction is isolated by filtering, pressing and drying. The dyestuff thus obtained when pulverized forms a red powder which dissolves in water to a red solution which solution on the addition of some concentrated soda lye becomes a little more bluish and darker and on the addition of some concentrated hydrochloric acid separates red flakes, whereas by adding some concentrated liquor ammoniae it is only changed very slightly.

The new coloring matter is soluble in alcohol with a yellow coloration and dissolves in concentrated sulfuric acid to a red solution, which on the addition of ice is precipitated in red flakes; it is very characteristic that a diluted solution of the dyestuff in concentrated sulfuric acid is bluish red or even blue-red. By the action of strong reducing agents the dyestuif is split up yielding parapaw -diaminophenylether disulfonic acid besides 1.2-aminonaphthol. This new dyestuff dyes wool without a mordant in an acid bath, and more especially in an acid bath containing acetic acid, pure and intense red tints which are very fast to milling.

It is obvious to those skilled in the art that I do not limit my invention to the foregoing example or to the details given therein. For instance if for the para-para,-diaminophenylether disulfonic acid a monosulfonic acid is substituted and if the. tetrazo-compound of such a monosulfonic acid is combined with two molecular proportions of beta-naphthol a red disazo-dyestufi is obtained which also dyes wool in an acid bath clear and intense red tints, very fast to milling.

Having now described my invention and the manner in which the same may be performed, what I claim is,

1. The hereinbefore described new red azo-dyestuffs which may be obtained by diazotizing a para-p ara -diarnino-phenylether sulfonio acid, combining the tetrazo-compound thus obtained with two molecular proportions of 'beta-naphthol, which new dyestuffs dye Woolfrom an acid bath without a mordant, and more especially from an acetic acid bath, clear and intense red tints which are fast to milling and which coloring matters when pulverized form a red powder and 'dissolve in water to a red solution; from which solution by the addition of mineral acids the free acid'of the dyestuff is precipitated, whereas by adding some concentrated liquor ammoniae the" aqueous solution is only slightly changed, which new dyestuffs are soluble inalcohol with a yellow coloration and dissolve in concentrated sulfuric'acid to a red'solution, and which new coloring matters by the action of strongreducing agents are split up, yielding a 'para para diaminophenylether sulfonic acid besides 1.2-aminonaphthol;

2, The hereinbefore described new red azo-dyestuff having in the'shape'of the sodium salt the formula:

/N=N'-O1'0H-,.OH. )2- i2 u I 7 N=NC10H,.OH.

which dyestuff may be obtainedby diazotizin the para para -diaminophenylether disu fonic acid, combining the tetrazo-compound thus obtained with two molecular proportions of beta-naphthol, which new dyestuif dyes wool from an acid bath without a mordant; and more especiallyfrom an acetic acid bath, clear and intense red tints WlliOll are fast to milling, and which coloring matter when pulverized forms a red powder which dissolves in water to a red solution, which solution on the addition of some concentrated soda-lye becomes a little more bluish and darker and on the addition of some concentrated hydrochloric acid 'separates red flakes, whereas "by adding someconcentrated liquor ammoniae" it isor'ily'chang ed very slightly, which new coloring matter dis solves in alcohol toa-yellow*solution=and in concentrated sulfuric acid to ared-solution, which solution on the additionof 'iceis' precipitated in red flakes, whereasadiluted solution of thedyestuff in concentratedsuh furic acid is bluish red or even blue-red, and which new"dyestuff by the action of strong reducing agents is split" up yielding; para para -diaminophenyl etl1er= disulfonic acid besides 1.2-aminonaphtholu In testimony whereof I have'herejunto' set my hand in presenceof two subscribing wit- IIBSSGS;

HUGO GELDERMANN;

Witnesses: v

WOLDEMAR HAUPT, V HENRY HAsPER. 

